File marks on old US coins made before the coins were struck. Used by the mint to adjust the weight of planchets before they were struck. After cutting the blank from a strip of metal they would be weighted, the lightweight ones would be remelted, the normal ones would be used, and the ones that were heavy would be sent to the adjusters who were usually women. After filing the excess material off, the blank would be reweighed and the process repeated if needed.